The invention relates to a method for producing and commissioning a transmission with a water-based lubricant, wherein the transmission consists of a housing and the rotary parts to be installed in the transmission. Transmissions of this kind are used in the most varied applications, in particular in motor vehicles as shift gearboxes, transfer gearboxes or axle drive gearboxes. The rotary parts are gears, shafts with their gears, couplings, bearing parts and, as the case may be, synchronizer rings. During operation in motor vehicles the power density is particularly high; due to this fact the gears are subject to high loads and sufficient cooling of the transmission requires special attention. Therein the lubricant also acts as a coolant transferring the frictional heat generated in the transmission to the gear housing or conveying it to a separate oil cooler.
WO 2007/098523 A2 by the applicant describes a method for commissioning a transmission, in which the lubricant consisting of water, an anti-freezing agent and a solid lubricant (for example, graphite) is mixed outside the transmission and then filled in the assembled, but still dry, transmission. During the first operation on the testing bench, which is common for high-performance transmissions, the lubricant is distributed in the transmission by the immerging gears. In this way a lubricating film is also formed on the gears. Therein the agitating effect of the gears prevents the lubricant from being demixed.
Tests have shown that in the case of said immersion lubrication during the first operation it takes a certain time until the gears are sufficiently moistened. Until then they run in a dry state, wherein abraded parts are formed, which are detrimental to the service life primarily of the bearings and the seal rings. In the case of pressure circulating lubrication it takes particularly long until the gears are moistened, which is why the method seemed to be less suitable for pressure circulating lubrication. This is a disadvantage because high-performance transmissions are often operated with pressure circulating lubrication. Furthermore it has been found that the coating produced in this way is not very robust and that the agitating effect of the gears under certain operating conditions is not sufficient.
During the manufacture of a transmission, after the mechanical processing of the rotary parts has been completed, they are rubbed with oil or grease and packed to protect them from corrosion in order to be transported at least to another workshop, but in most cases to a transmission manufacturer at a different location. There they are then degreased and finally installed in the housing. These procedures cause considerable labor and plant costs.
Indeed it is known from DE 198 54 592 A and from U.S. Pat. No. 3,719,598 to use rinsing liquids containing boron compounds during the machining of metal parts. In accordance with U.S. Pat. No. 3,719,598 said rinsing liquids also contain fatty acid esters. Rinsing liquids for this totally different purpose almost exclusively serve to carry off heat. They are not allowed to leave any residues on the workpiece.